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Passing Data to and from External Predicates in C++
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<H2 CLASS="section"><A NAME="htoc134">B.4</A>&nbsp;&nbsp;Passing Data to and from External Predicates in C++</H2>
These two functions are only meaningful inside C++ functions that have been
called from ECL<SUP><I>i</I></SUP>PS<SUP><I>e</I></SUP> as external predicates.
<DL CLASS="description" COMPACT=compact><DT CLASS="dt-description">
<B>EC_word		EC_arg(int i)</B><DD CLASS="dd-description"><BR>
	If inside a C++ function called from ECL<SUP><I>i</I></SUP>PS<SUP><I>e</I></SUP>, this returns the
	i'th argument of the call.<BR>
<BR>
<DT CLASS="dt-description"><B>int		unify(EC_word,EC_word)</B><DD CLASS="dd-description"><BR>
	Unify the two given pwords. Note that, if attributed variables
	are involved in the unification, the associated unification handlers
	as well as subsequent waking will only happen once control is
	returned to ECL<SUP><I>i</I></SUP>PS<SUP><I>e</I></SUP>.<BR>
<BR>
<DT CLASS="dt-description"><B>int		EC_word::unify(EC_word)</B><DD CLASS="dd-description"><BR>
	Similar, but a method of EC_word.
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